Shelf



FIG. 1 is a bottom view of a shelf;

FIG. 2 is a bottom rear perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a top front perspective view thereof;

FIG. 5 is a bottom front perspective view thereof;

FIG. 6 is a left side view thereof, with the right side view thereof appearing similar; and,

FIG. 7 is a top view thereof. 

CLAIM The ornamental design for a shelf, as shown and described. 